1. Field of the Invention
The present invention relates to a tilt angle adjuster for a form measuring device.
2. Description of Related Art
Known examples of form measuring devices include a surface characteristic measuring apparatus which measures surface roughness, unevenness, and undulation (Japanese Patent No. 5,000,894). The surface characteristic measuring apparatus supports a stylus having a contact pin at a forefront end such that the stylus is capable of swinging, and detects roughness, unevenness, and undulation of a surface of a measured object based on an amount of swing of the stylus when the contact pin profiles and scans over the surface of the measured object. FIG. 1 illustrates a conventional surface characteristic measuring apparatus 50. The surface characteristic measuring apparatus 50 is provided with a measuring device main body 10 and a support stand 20.
The measuring device main body 10 includes a stylus 12 having a contact pin 11 at a forefront end; a detection portion 13 swingably supporting the stylus 12 and also detecting an amount of swing of the stylus 12; and an X slide mechanism 14 advancing and withdrawing the detection portion 13 in an X axis direction.
In FIG. 1, the X axis runs from left to right, a Y axis runs from a front to a back of the drawing sheet, and a Z axis runs from a bottom upwards.
The support stand 20 includes a base 21; a Z column 22 standing upright on the base 21; and a Z slider 23 provided so as to be capable of rising and lowering in a vertical direction (Z axis direction) on the Z column 22.
In this example, the X slide mechanism 14 is mounted to the Z slider 23 and the measuring device main body 10 is supported on the support stand 20, but this does not mean that the X slide mechanism 14 is attached directly to the Z slider 23. Instead, a swivel plate 30 is interposed between the Z slider 23 and the X slide mechanism 14. The swivel plate 30 enables the measuring device main body 10 to tilt with an axis parallel to the Y axis as a rotation axis. In a case where a measured surface W1 is an inclined surface, for example, the X slide mechanism 14 is tilted by the swivel plate 30 such that the measured surface W1 and a drive direction of the X slide mechanism 14 are parallel. Accordingly, the roughness, unevenness, and undulation of the measured surface W1 are brought into a vertical movement range (measurement range) of the stylus 12, enabling tracing measurement of the inclined measured surface W1.
A tilt angle of the measuring device main body 10 can be reliably modified and adjusted by the swivel plate 30. However, the vertical movement range (measurement range) of the stylus 12 is on the order of hundreds of micrometers. Therefore, when adjusting an orientation to bring the drive direction of the X slide mechanism 14 parallel with the measured surface W1, fine adjustments must be made within a range of hundreds of micrometers. In the end, the tilt angle of the measuring device main body 10 must be adjusted within a range of plus or minus 1°. However, in a case that only provides a rotation axis (tilt axis) such as the swivel plate 30, such fine adjustment is rather difficult and an operator overshoots and goes back several times to locate an appropriate position. This requires a fair amount of time and effort. When time and effort is required for tilt adjustment, work efficiency (measurement efficiency) is reduced.